Mechanism on Barrierless Carrier Injection in Quantum Dot Light-Emitting Diodes
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초록
내용
Balancing electron and hole injection has being considered to a key issue in quantum dot light-emitting diodes (QLEDs). The organic−inorganic hybrid structure of QLEDs employing ZnO electron transport layers (ETLs) and organic hole transport layers successfully mitigated the carrier injection imbalance problem, consequently, realized QLEDs with low threshold and high efficiency. However, it is yet to be solved how the ZnO ETL enable to balanced and barrierless carrier injection into quantum dots (QDs). We unveil the mechanism on the barrierless carrier injection in hybrid QLEDs. In macroscopic viewpoint, the Fermi level aligned to the surface states of QDs causes the electrostatic potential gain for hole injection. In microscopic viewpoint, the carriers injected in individual QDs regulate the injection rate of opposite carriers with the Coulombmic interaction. Our finding suggests generalized operation mechanism on hybrid QLEDs and would paves the way for efficient and stable QLEDs.